Table III.
Comparison of the features of TCRμ, shark NAR TCR, and mammalian conventional TCRα/δ.
| Locus | Model Species | C gene | Double V | Somatic recombination | Leader sequence | No. of D segments used | CDR3 length$ (mean) | V nature | Ref | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| N-terminal | C-proximal | N-terminal | C-proximal | N-terminal | C-proximal | N-terminal | C-proximal | N-terminal | C-proximal | |||||
| TCRμ | Platypus | Cμ | Yes | Yes | Yes | Yes | No | 2-4 | 0? | 9-22(14) | 9-12(11) | VH Clan III | VH Clan III | herein |
| Opossum | Cμ | Yes | Yes | No§ | Yes | Yes# | 1-3 | NA* | 8-29(17) | 11 | VH-related | VH-related | 4 | |
| NAR-TCR | Nurse shark | Cδ | Yes | Yes | Yes | Yes | No | 1 | 1-2 | 9-25(16) | 9-27(16) | V-NAR | Vδ | 22 |
| TCRα/δ | Xenopus | Cδ1 | No | Yes | NA | Yes | NA | 1-2 | NA | 7-20(13) | NA | Vα, Vδ, VHδ (VH Clan II) | NA | 23 |
| TCRα/δ | Human | Cδ | No | Yes | NA | Yes | NA | 2-3 | NA | 8-12(15) | NA | Vα, Vδ | NA | 24 |
| TCRα/δ | Mouse | Cδ | No | Yes | NA | Yes | NA | 2 | NA | 6-19(13) | NA | Vα, Vδ | NA | 24 |
$
Range in codons
§
The C proximal V in marsupial TCRμ is a germ-line joined V
#
Fused to the V domain exon as the result of retrotransposition
*
Not applicable